A PC Speaker (also referred to as a beeper or buzzer) is a simple audio device capable of making a primitive sound. It usually consists of a timing chip that sends an oscillating electric signal to a speaker which produces sound wave in the shape of a square wave. While the name suggests that the speaker exists only on PCs, pretty much every home computer brand and model since the 1980s features a PC speaker.
The speaker was originally intended to give simple feedback beeps to the user before video output had initialized, and as such, are included in nearly every model of personal computer. Of course, game programmers began taking advantage of them in games by pushing sound effects, music, and even voice through them.
The earliest PC speakers were 2.25 inch magnetic speakers, though these slowly decreased in size as computer manufacturers depended on them less. The magnetic speakers were eventually replaced with a 1 cm piezoelectric tweeter, often times, soldered directly on the motherboard. High fidelity sound cards were being sold in the late 1980s, and by the late 1990s, they were built into most motherboards, so game developers stopped supporting PC speaker output. The Windows systems support it even now, but only with 32-bit systems and lower; the 64-bit systems dropped the support since there was a problem of sending signals through it due to the different software.
It's hard to say precisely when the first PC speaker was used since it's nothing more than a simple speaker attached to a timing chip in a computer. PC Speaker-esque sound generators have been used in the earliest arcade machines like Pong, and the latter came in November, 1972. PC Speaker itself dates back at least to January, 1977, when the Commodore PET came. The first mass-produced computer with a built-in PC speaker (more inportantly, fluently used in video game music) was the IBM 5150 which was released in August, 1981. Most subsequent home computers released in the 1980s included a PC speaker.
Despite having 1-bit fidelity, the PC speaker, when afforded enough clock cycles from the CPU, can produce impressive sounding audio. Several games were able to play digital audio samples through it, even speech which can be heard in games like Beyond Castle Wolfenstein (PCB), Castle Wolfenstein (DOS), Last Half of Darkness (DOS), and Total Eclipse (DOS). Later games on the ZX Spectrum were able to simulate multiple voices by essentially combining the waveforms of multiple instruments in memory into a single waveform and playing the output.
One of the more popular timing chips used to control the PC speaker is the Intel 8253.
The buzzer on a ZX Spectrum 48K.
Most emulators that emulate an early PC also emulate a PC speaker. However, DOSBox 0.74 doesn't play PMB files and the samples in Perestroika (DOS), possibly due to a timer bug already fixed on SourceForge.
- en.wikipedia.org/wiki/PC_speaker - Wikipedia.